A number of different design solutions are currently employed for dispensing of dental floss and other flexible elongated materials. None of them is free from some drawbacks.
For instance, functioning of-most of the known in this field devices (such as U.S. Pat. Nos. 3,861,406, 5,020,554, 5,038,806, 5,060,681, 5,188,133, or "FlossMate" by John O. Butler Co.) which require to anchor floss under tension after it was fed comprises a chain of consequent actions performed either manually, that complicates exploitation, or by special mechanisms, that complicates the device itself.
Devices of another group (such as U.S. Pat. Nos. 4,790,336 and 5,141,008) combine feeding and tensioning functions by employing so called differential material feeding mechanisms with supply and take-up capstans of different diameters. These devices, though quite simple in design, still require frequent interruptions for tensioning/feeding and for used floss disposing.
Besides that, all of the above mentioned devices share two other deficiencies inherited from their design. First, if due to its stretchability floss gets too loose in a course of teeth cleaning manipulations, it has to be refed again in order to restore desired tension at the area of use. Second, because of relatively high floss tension required by those devices to function the length of floss in the area of use resembles a straight line segment which can only have one point contact with a generally convex surface of a tooth, thus reducing efficiency of a teeth cleaning process.
Still a device like one disclosed in U.S. Pat. No. 3,734,107 with the differential feeding mechanism, though provides some means for taking up some very limited amount of slack in stretched floss, nevertheless retains all other drawbacks of its group described above.
Yet the dental floss applicator described in U.S. Pat. No. 3,906,963, despite providing good floss tension control means for improved teeth cleaning efficiency, still fails to relieve a user of floss feeding, floss anchoring, and used floss disposing chores.